Women who are physically active at midlife, including those whose only exercise is walking, are more likely than sedentary women to have exceptionally good health in older age, according to an analysis of more than 2 decades of data from the Nurses' Health Study.
Researchers led by Dr. Qi Sun of the Harvard School of Public Health, Boston, studied how women might reach “successful survival.” The team defined that goal as living to at least age 70 with no impairment in cognitive function, no limitations on moderate activities, only moderate limitations on demanding physical activities, no mental health limitations, and no serious diseases.
The researchers wrote that their study “documented a strong, positive association between midlife leisure-time physical activity and the odds of successful survival or exceptional overall health in later life.” Even moderate-intensity walking raised the likelihood that women would “maintain physical and cognitive integrity and remain free of major chronic illnesses,” the team reported (Arch. Intern. Med. 2010;170:194-201).
Previous studies have not addressed the relationship between activity and healthy aging in women specifically, even though women tend to live longer than men and stand to benefit more from successful survival. “The notion that physical activity can promote successful survival rather than simply extend the lifespan may provide particularly strong motivation for initiating activity,” Dr. Sun and his colleagues noted.
The investigators analyzed data on 13,535 women participating in the Nurses' Health Study. The participants were assessed initially in 1976, when they were aged 30-55 years, and have been followed ever since. The type, timing, and intensity of their physical activity were calculated in 1986, when their mean age was 60 years.
At follow-up during 1995-2001, 1,456 (approximately 11%) of these women were found to be successful survivors.
The positive association between physical activity during midlife and successful survival was strong within each group of women categorized by body mass index, indicating that physical activity contributes to optimal health in both lean and overweight women, Dr. Sun and his colleagues said.
Several activities were individually associated with successful survival, including jogging, running, playing tennis, doing aerobics, and walking. Independently of total physical activity levels, walking pace was strongly associated with health in old age. “Compared with women whose walking pace was easy, women with a moderate walking pace had a 90% increase in the odds of successful aging; women whose walking pace was brisk or very brisk had a 2.68-fold increased odds,” the researchers said.
In their report, they noted that an estimated 85% of Americans do not engage in any regular vigorous physical activity, but nearly 50% at least walk for exercise. “Given that walking is a sustainable exercise that can often be easily incorporated into people's daily schedules, our observations provide initial support for the consideration of walking in broad public health recommendations,” Dr. Sun and his colleagues added.
The study was limited in that the participants were primarily of European ancestry and “largely healthy” at age 60, so the findings may not be applicable to other populations, the researchers said.
The study was supported by grants from NIH and the Boston Obesity Nutrition Research Center. Dr. Sun disclosed a postdoctoral fellowship supported by Unilever Corporate Research.